IV-J-1 Self-diffusion Coefficients of a Reentrant Liquid Crystal CBOBP

Self-diffusion coefficient tensors of a reentrant liquid crystal CBOBP were measured in the high and low temperature SA phases. In the high temperature SA phase, the diffusion coefficient component D// is larger than D⊥. The two activation energies are similar. This property resembles that of the nematic phase, and indicates that the layer structure of the high temperature SA phase is disordered remarkably. In the low temperature SA phase, absolute values of the selfdiffusion coefficient components, D// and D⊥, are close to each other, in contrast with the diffusion coefficient components in the high temperature SA phase. The activation energy for D// is much higher than that for D⊥. This suggests a firm layer structure. It is also interesting to note that the activation energies for D⊥ are similar in the high and low temperature SA phases, and the values of D⊥ are found on one straight line through both phases. Taking these in mind there seems to be no change in molecular interaction and molecular arrangement in the two SA phases, as far as the perpendicular components concern. The change in molecular interaction and structure seemed to have occurred in the parallel components.